Advanced Finance

Securitisation Waterfalls

In structured credit the assets set the total and the waterfall decides who gets it. Learn to read a priority of payments the way a rating analyst does, and to find the trigger that will change the answer.

  • Expert
  • 13 min total
  • 13 chapters

What decision this helps you make: Where in a capital structure the money actually goes under stress, which trigger flips the deal from pro rata to sequential, and what a given note is really protected by.

What this topic is

A securitisation waterfall is the contractual order in which cash collected from a pool of assets is applied. Interest collections and principal collections are usually governed by separate schedules. Each schedule pays fees, then the most senior note, then tests a set of conditions, then continues downward - with cash diverted, trapped, or redirected whenever a test fails. The waterfall is the deal.

Why it matters

Two securitisations backed by identical assets can produce completely different outcomes for the same tranche depending on the waterfall. Whether principal amortises sequentially or pro rata, whether excess spread is trapped or released, whether a swap counterparty ranks above or below the notes on termination, whether the servicer's advances are reimbursed before or after the noteholders - each of these decides real money. Credit analysis of the pool tells you how much cash there will be. Only the waterfall tells you where it goes.

Who should learn it

Structured credit investors and analysts, securitisation lawyers and structurers, bank treasury and funding teams, rating analysts, and anyone who has to model an asset-backed deal rather than take a rating on trust.

What you will understand

  • How interest and principal waterfalls are constructed and why they are usually separate
  • The mechanics of excess spread, reserve funds, principal deficiency ledgers, and cash trapping
  • Why the switch between sequential and pro rata amortisation is the single most contested feature in any deal
  • How swap counterparty ranking and flip clauses were litigated, and where the law stands as decided to date

Prerequisites

Common misconception

The most common mistake is to think of credit enhancement as a stack of tranches - so many points of subordination beneath your note and that is your protection. Subordination is only the last line. Before a single unit of subordination is consumed, losses are absorbed by excess spread, then by a reserve fund, then by cash that the waterfall traps and applies to principal rather than releasing. In the worked example in this lesson, roughly 147 basis points a year of excess spread and a 1.5% reserve fund absorb losses before any note is touched at all. And that ordering runs the other way too: a deal with generous subordination but no excess spread is far weaker in a slow-burn loss scenario than the tranche thickness suggests.